The correct option is D None of the above
When Napoleon along with his mighty army invaded Russia, the grand army was defeated by a tiny bacterium called Rickettsia prowazekii which infected the French soldiers and caused a unique disease called Typhus. The disease got spread by a human louse (bug) where the bacteria grew in the gut of these pests and were excreted in their faeces. Rickettsia can remain viable and virulent in dried faeces of lice for many days, and gains entry into the human body through the wound caused by a louse bite. This disease killed almost 500,000 grand French soldiers. So as it turns out, the French were laid low, more efficiently by this microscopic organism and its epidemic, than the resistance put up by the Russian Army.